Interaction between two listboxes)

Suitable:
. NET 2.0
Vs2005
Effect:

ASPX page:

< Table >
< Tbody >
< Tr >
< TD >
< ASP: ListBox ID = "Lbleft" Runat = "Server" Selectionmode = "Multiple" >
< ASP: listitem > Add name </ ASP: listitem >
< ASP: listitem > Date of birth </ ASP: listitem >
</ ASP: ListBox >
</ TD >
< TD Style = "Width: 27px" >
< ASP: button ID = "Btntoright" Runat = "Server" Text = ">"
Onclick = "Btntoright_click"   />
< BR />
< ASP: button ID = "Btntoleft" Runat = "Server" Text = "<"
Onclick = "Btntoleft_click"   />
</ TD >
< TD Style = "Width: 3px" >
< ASP: ListBox ID = "Lbright" Runat = "Server"
Selectionmode = "Multiple" > </ ASP: ListBox > </ TD >
</ Tr >
</ Tbody >
</ Table >
< ASP: Label ID = "Lblmsg" Runat = "Server" > </ ASP: Label >

Code As follows: Using System;
Using System. Data;
Using System. configuration;
Using System. collections;
Using System. Web;
Using System. Web. Security;
Using System. Web. UI;
Using System. Web. UI. webcontrols;
Using System. Web. UI. webcontrols. webparts;
Using System. Web. UI. htmlcontrols;
Public   Partial   Class Test1: system. Web. UI. Page
{
Protected   Void Page_load ( Object Sender, eventargs E)
{
}
Protected   Void Btntoright_click ( Object Sender, eventargs E)
{
If (Lbleft. selecteditem ! =   Null )
{
Additemfromsourcelistbox (lbleft, lbright );

Removeselecteditem (lbleft );

Lblmsg. Text = "" ; // Note: Why is this line required?

Foreach (Listitem item In Lbright. Items)
{
If (Item. Selected)
Lblmsg. Text + = Item. text;
}
}
}
Protected   Void Btntoleft_click ( Object Sender, eventargs E)
{
If (Lbright. selecteditem ! =   Null )
{
Additemfromsourcelistbox (lbright, lbleft );
Removeselecteditem (lbright );
}
}
Private   Void Removeselecteditem (ListBox listcontrol)
{
While (Listcontrol. selectedindex ! =   - 1 )
{
Listcontrol. Items. removeat (listcontrol. selectedindex );
}
}

Private   Void Additemfromsourcelistbox (ListBox sourcebox, ListBox targetbox)
{
Foreach (Listitem item In Sourcebox. Items)
{
If (Item. Selected =   True   &&   ! Targetbox. Items. Contains (item ))
{
Targetbox. Items. Add (item );
}
}
}
}